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Biological complexity presents challenges for understanding natural phenomenon and engineering new technologies, particularly in systems with molecular heterogeneity. Such complexity is present in myosin motor protein systems, and computational modeling is essential for determining how collective myosin interactions produce emergent system behavior. We develop a computational approach for altering myosin isoform parameters and their collective organization, and support predictions with in vitro experiments of motility assays with α-actinins as molecular force sensors. The computational approach models variations in single myosin molecular structure, system organization, and force stimuli to predict system behavior for filament velocity, energy consumption, and robustness. Robustness is the range of forces where a filament is expected to have continuous velocity and depends on used myosin system energy. Myosin systems are shown to have highly nonlinear behavior across force conditions that may be exploited at a systems level by combining slow and fast myosin isoforms heterogeneously. Results suggest some heterogeneous systems have lower energy use near stall conditions and greater energy consumption when unloaded, therefore promoting robustness. These heterogeneous system capabilities are unique in comparison with homogenous systems and potentially advantageous for high performance bionanotechnologies. Findings open doors at the intersections of mechanics and biology, particularly for understanding and treating myosin-related diseases and developing approaches for motor molecule-based technologies.
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Biología Computacional , Modelos Teóricos , Contracción Muscular/fisiología , Músculos/fisiología , Miosinas/metabolismo , Actinas/metabolismo , Actomiosina/metabolismo , Fenómenos Biomecánicos/fisiología , HumanosRESUMEN
In complex systems with stochastic components, systems laws often emerge that describe higher level behavior regardless of lower level component configurations. In this paper, emergent laws for describing mechanochemical systems are investigated for processive myosin-actin motility systems. On the basis of prior experimental evidence that longer processive lifetimes are enabled by larger myosin ensembles, it is hypothesized that emergent scaling laws could coincide with myosin-actin contact probability or system energy consumption. Because processivity is difficult to predict analytically and measure experimentally, agent-based computational techniques are developed to simulate processive myosin ensembles and produce novel processive lifetime measurements. It is demonstrated that only systems energy relationships hold regardless of isoform configurations or ensemble size, and a unified expression for predicting processive lifetime is revealed. The finding of such laws provides insight for how patterns emerge in stochastic mechanochemical systems, while also informing understanding and engineering of complex biological systems.
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Modelos Moleculares , Miosinas/química , Miosinas/metabolismo , Fenómenos Biomecánicos , Biología Computacional , Simulación por Computador , Isoformas de Proteínas , Reproducibilidad de los Resultados , Procesos EstocásticosRESUMEN
Scientific literacy can also be described as a level of public understanding of science that encourages one to act in concert with scientific consensus. Investigating actions concerned with environmental conservation, we examine the context specificity of this form of scientifically literate action and the differential motivations that predict such action across contexts. We report on a large sample of employees of a mixed urban/ rural county in the USA, representing a diverse range of careers, who completed an anonymous survey about their environmental conservation actions at home, at work and in the public sphere. Results indicate that individuals engage at different action levels overall and for different reasons across contexts; limited support was found for the importance of perceived knowledge attainment ability in predicting scientifically informed actions. Implications for policy and program designers and scholars interested in scientific literacy are discussed.
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Conservación de los Recursos Naturales , Alfabetización Informacional , Ciencia , Comunicación , Comprensión , Medio Oeste de Estados Unidos , Encuestas y CuestionariosRESUMEN
Reading, presenting, and discussing peer-reviewed scientific reports, case studies, and reviews are essential to modern biology education. These exercises model crucial aspects of students' future professional activities and introduce the students to the current scientific concepts and methodology, data analysis, and presentation. A common format for working with primary literature is a journal club: presenting and discussing research literature in front of peers, which has many merits. However, in large modern classrooms, this format is very time-consuming and stressful, especially since presenting is not a commonly taught skill. We argue that student groups for whom the current educational and professional paradigms present a challenge due to a historical lack of representation or wellness issues are deprived of a key educational opportunity. To solve this problem, we formulated an approach called Peer-Reviewed Presentation Exchange (PRPE), which focuses on collaborative analysis, presentation, and review of research literature that includes (i) voice-narrated research presentations by students, (ii) checklists generated by the instructor to establish expectations for an informative presentation or review, and (iii) presentation assignment and peer review process. We tested this approach in an undergraduate cell biology class over 3 years. Pre- and post-assessments show significant gains in self-efficacy and knowledge not only by students who presented but also by the students who reviewed the presentations; therefore, peer-reviewed presentations are an effective tool for learning. Exit surveys show that the approach is seen as beneficial by most students. Our approach allows every student to speak and ask questions in a low-stress creative environment. It is an excellent customizable, trackable, and scalable low-stakes assessment tool.
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Complex problem solving in naturalistic environments is fraught with uncertainty, which has significant impacts on problem-solving behavior. Thus, theories of human problem solving should include accounts of the cognitive strategies people bring to bear to deal with uncertainty during problem solving. In this article, we present evidence that analogy is one such strategy. Using statistical analyses of the temporal dynamics between analogy and expressed uncertainty in the naturalistic problem-solving conversations among scientists on the Mars Rover Mission, we show that spikes in expressed uncertainty reliably predict analogy use (Study 1) and that expressed uncertainty reduces to baseline levels following analogy use (Study 2). In addition, in Study 3, we show with qualitative analyses that this relationship between uncertainty and analogy is not due to miscommunication-related uncertainty but, rather, is primarily concentrated on substantive problem-solving issues. Finally, we discuss a hypothesis about how analogy might serve as an uncertainty reduction strategy in naturalistic complex problem solving.
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Solución de Problemas/fisiología , Incertidumbre , Adulto , Humanos , Investigación CualitativaRESUMEN
Research in a range of disciplines shows that many undergraduate students struggle with aggregating complex knowledge components into a complete picture and incorporating research literature into the learning process. To build and improve on the practice of project-based approaches to teaching cell biology, we transformed an undergraduate cell biology class by introducing the concept of storylines that are selected by groups of students for development throughout the semester. Each storyline integrates molecular and organellar concepts discussed during the semester into the cell- and tissue-level functions, conditions, or diseases shared and discussed during online poster sessions. Three semester-long studies conducted with an undergraduate cell biology class utilized pre- and postassignment assessments of self-efficacy and content knowledge (administered three times during the semester), and these studies showed that both parameters were significantly improved following each assignment. Specifically, student self-efficacy showed large gains, preassignment to postassignment (pre-post) [F (1,13) = 47.8, P < .001], and content knowledge showed moderate pre-post gains [F (1,12) = 14.5, P < 0.002]. Attitude surveys administered at the end of the semester suggest that the approach is seen as beneficial and enriching. We conclude that it is possible to integrate multiple levels of material in a complicated class by using storytelling and that such integration is positive and useful.
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[This corrects the article DOI: 10.3389/fpsyg.2021.788474.].
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Neuroimaging studies of text comprehension conducted thus far have shed little light on the brain mechanisms underlying strategic learning from text. Thus, the present study was designed to answer the question of what brain areas are active during performance of complex reading strategies. Reading comprehension strategies are designed to improve a reader's comprehension of a text. For example, self-explanation is a complex reading strategy that enhances existing comprehension processes. It was hypothesized that reading strategies would involve areas of the brain that are normally involved in reading comprehension along with areas that are involved in strategic control processes because the readers are intentionally using a complex reading strategy. Subjects were asked to reread, paraphrase, and self-explain three different texts in a block design fMRI study. Activation was found in both executive control and comprehension areas, and furthermore, learning from text was associated with activation in the anterior prefrontal cortex (aPFC). The authors speculate that the aPFC may play a role in coordinating the internal and external modes of thought that are necessary for integrating new knowledge from texts with prior knowledge.
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Cognición/fisiología , Comprensión/fisiología , Lectura , Adolescente , Adulto , Mapeo Encefálico , Corteza Cerebral/fisiología , Instrucción por Computador , Interpretación Estadística de Datos , Función Ejecutiva/fisiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Red Nerviosa/fisiología , Corteza Prefrontal/fisiología , Desempeño Psicomotor/fisiología , Adulto JovenRESUMEN
Participation is an important factor in team success. We propose a new metric of participation equality that provides an unbiased estimate across groups of different sizes and across those that change size over time. Using 11 h of transcribed utterances from informal, fluid, colocated workgroup meetings, we compared the associations of this metric with coded equality of participation and standard deviation. While coded participation and our metric had similar patterns of findings, standard deviation had a somewhat different pattern, suggesting that it might lead to incorrect assessments with fluid teams. Exploratory analyses suggest that, as compared with mixed-age/status groups, groups of younger faculty had more equal participation and that the presence of negative affect words was associated with more dominated participation. Future research can take advantage of this new metric to further theory on team processes in both face-to-face and distributed settings.
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Relaciones Interpersonales , Participación Social , Adulto , Femenino , Humanos , Masculino , Proyectos de Investigación , Conducta SocialRESUMEN
This study investigated the longer-term impacts (i.e., into the next semester) of trained peer feedback in comparison with teacher feedback on students' writing development and writing motivation. Sections of an EFL writing course were randomly assigned to either teacher feedback or trained peer feedback conditions across two semesters. In the first semester, during their writing class, students either received training in how to implement peer feedback or simply studied models of writing (that were also used in the training work). In the second semester, students either received teacher or peer feedback across multiple assignments. Writing competence, writing self-efficacy, and writing self-regulated learning were assessed at the beginning and end of the second semester. Trained peer feedback and teacher feedback had similar positive effects on the improvement of writing competence and writing self-efficacy. However, trained peer feedback led to a significant enhancement of students' autonomous motivation relative to no such growth from teacher feedback.
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While pointing out important features of cognitive science, Núñez et al. (2019) also argue prematurely for the end of cognitive science. I discuss problematic analytic features in the application of hierarchical cluster analysis to journal citation data. On the conceptual side, I argue that the research programs framework of Lakatos may not be so wisely applied to cognitive science. Further, the diversity of structure in cognitive science departments may represent a rational, strategic adaptation by an interdisciplinary department to cognitive and other resource challenges rather than the sign of low progress on a discipline.
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Ciencia Cognitiva , Árboles , Análisis por Conglomerados , FísicaRESUMEN
Gene expression is a difficult topic for students to learn and comprehend, at least partially because it involves various biochemical structures and processes occurring at the microscopic level. Designer Bacteria, a design-based learning (DBL) unit for high-school students, applies principles of DBL to the teaching of gene expression. Throughout the 8-week unit, students genetically engineer bacteria to meet a need in their own lives. Through a series of investigations, discussions, and design modifications, students learn about the molecular processes and structures involved in gene expression, and how these processes and structures are dependent upon various environmental variables. This article is intended to describe the Designer Bacteria unit and report preliminary results of student progress and performance on pre-unit and post-unit assessments. Teacher experiences and student progress indicate that Designer Bacteria successfully taught core aspects of gene expression through DBL.
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BACKGROUND: In contrast to the extensive research on socioeconomic gaps in reading and math achievement, little attention has been given to socioeconomic disparities in science skills, particularly during the early years of schooling. This emphasis on later years may be problematic because large socioeconomic disparities emerge in the early years, thus it is crucial to document the size of disparities in science achievement and begin unpacking the range of factors that contribute to these disparities. Additionally, it is crucial to know which components of socioeconomic status are more strongly linked to children's science skills so that resources can be more effectively targeted to address disparities. Using nationally representative data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (N = 9250), this study examines disparities in science achievement across elementary and middle school related to parental income and parental education separating their effects from each other and from a range of confounding factors. Additionally, it considers whether characteristics of children, families, and schools are pathways through which socioeconomic disparities emerge. RESULTS: Results show moderate gaps in science achievement related to both household income and parental education. The primary pathways through which parental education and family income influenced science achievement was through mathematics and reading achievement. For parental education gaps, smaller indirect effects also operated through access to informal science learning opportunities both inside and outside of the home environment. CONCLUSION: First, this study highlights the importance of considering the contributions of multiple measures of socioeconomic status, instead of a composite. Second, it shows that socioeconomic disparities in science achievement emerge early and that programs and policies aimed at addressing these gaps may need to target children during the early elementary and preschool years. Third, our findings suggest that elementary instructional approaches that simultaneously address science instruction with reading and/or mathematics instruction will likely be especially important for improving overall science outcomes.
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BACKGROUND: A major concern in science education involves the under-representation of many groups in science and technology fields, especially by gender (Brotman and Moore, J Res Sci Teach 45:971-1002, 2008; Clark Blickenstaff, Gend Educ 17:369-386, 2006), stemming from an intersection of systemic obstacles (Cantú, Equity Excell Educ 45:472-487, 2012; Rosa and Mensah, Phys Rev Phys Educ Res 12:020113, 2016). Research on persistence of minoritized populations within science trajectories has often highlighted identity as particularly important (Archer et al., Sci Educ 94:617-639, 2010; Barton and Calabrese, Am Educ Res J 50:37-75, 2007; Barton et al., Am Educ Res J 50:37-75, 2013; Merolla and Serpe, Soc Psychol Educ 16:575-597, 2013). RESULTS: This study quantitatively investigated the nature of science identity in over 1300 seventh and ninth grade students from a range of urban US public schools using survey data on science identity, choice preferences, and optional science experiences. Factor analyses validated this conceptualization of science identity as integrating perceived internal and external identity components. Regression analyses revealed the importance of this conceptualization of science identity for driving students' choices at this crucial developmental period. Furthermore, science identity had a complex differential function in supporting students' optional science choices by gender. CONCLUSIONS: The novel contribution to the science identity field highlights the specific multi-component ways in which students endorse science identity in middle school and early high school. There was an important finding that science identity has a complex differential function in supporting student's optional science choices by gender. Thus, at this age, developing a strong science identity is especially critical for girls.
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Introduction: Adults can represent numerical information in nonsymbolic and symbolic formats and flexibly switch between the two. While some studies suggest a strong link between the two number representation systems (e.g., Piazza, Izard, Pinel, Le Bihan, & Dehaene, 2004 Neuron, 44(3), 547), other studies show evidence against the strong-link hypothesis (e.g., Lyons, Ansari, & Beilock, 2012 Journal of Experimental Psychology: General, 141(4), 635). This inconsistency could arise from the relation between task demands and the closeness of the link between the two number systems. Methods: We used a passive viewing task and event-related potentials (ERP) to examine the temporal dynamics of the implicit integration between the nonsymbolic and symbolic systems. We focused on two ERP components over posterior scalp sites that were found to be sensitive to numerical distances and ratio differences in both numerical formats: a negative component that peaks around 170 ms poststimulus (N1) and a positive component that peaks around 200 ms poststimulus (P2p). We examined adults' (n = 55) ERPs when they were passively viewing simultaneously presented dot quantities and Arabic numerals (i.e., nonsymbolic and symbolic numerical information) in the double-digit range. For each stimulus, the nonsymbolic and symbolic content either matched or mismatched in number. We also asked each participant to estimate dot quantities in a separate behavioral task and observed that they tended to underestimate the actual dot quantities, suggesting a need to adjust the match between nonsymbolic and symbolic information to reflect the perceived quantity of the nonsymbolic information. Results: Using this adjustment, participants showed greater N1 and P2p amplitudes when perceived dot quantities matched Arabic numerals than when there was a mismatch. However, no differences were found between the unadjusted match and mismatch conditions. Conclusion: Our findings suggest that adults rapidly integrate nonsymbolic and symbolic formats of double-digit numbers, but evidence of such integration is best observed when the perceived (rather than veridical) dot quantity is considered.
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Encéfalo/fisiología , Electroencefalografía/métodos , Matemática , Adulto , Potenciales Evocados , Femenino , Humanos , Masculino , Análisis y Desempeño de Tareas , Adulto JovenRESUMEN
Private speech used by high-functioning children with autistic spectrum disorders (ASD) (n = 33) during two executive functioning tasks was compared to that of typically developing children (n = 28), and children with ADHD (n = 21). Children with ASD were as likely as others to talk to themselves and their speech was similarly relevant and likely to appear in moments of task difficulty. Unlike others, children with ASD were more likely to get items correct when they were talking than when they were silent. Group differences in performance were observed when children were silent but not when children were talking. Findings suggest that autistic children talk to themselves in relevant ways during problem-solving and that such speech is helpful in normalizing their executive performance relative to controls.
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Trastorno por Déficit de Atención con Hiperactividad/epidemiología , Trastorno Autístico/epidemiología , Trastornos del Conocimiento/epidemiología , Habla , Conducta Verbal , Adolescente , Trastorno Autístico/diagnóstico , Niño , Trastornos del Conocimiento/diagnóstico , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas , Índice de Severidad de la EnfermedadRESUMEN
It is notoriously difficult for people to adaptively apply formal mathematical strategies learned in school to real-world contexts, even when they possess the required mathematical skills. The current study explores whether a problem context's mechanism can act as an "embodied analogy" onto which abstract mathematical concepts can be applied, leading to more frequent use of formal mathematical strategies. Participants were asked to program a robot to navigate a maze and to create a navigation strategy that would work for differently sized robots. We compared the strategy complexity of participants with high levels of mechanistic knowledge about the robot against participants with low levels of mechanistic knowledge about the robot. Mechanistic knowledge was significantly associated with the frequency and complexity of the mathematical strategies used by participants, suggesting that learning to recognize a problem context's mechanism may promote independent mathematical problem solving in applied contexts.
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BACKGROUND: Much of science, technology, engineering, mathematics, and medical (STEMM) education policy and research centers around developing the upper levels of the STEMM workforce sector. However, there are many positions in this workforce, "middle-skill careers," that are largely responsible for executing the innovations and are largely ignored in STEMM education research. RESULTS: Using data from the National Educational Longitudinal Study of 1988, we found differences in what predicts STEMM-related vs. non-STEMM careers across skill-level. For instance, underrepresented minorities and those exhibiting school transgressions are more likely to be working in middle-skill STEMM fields than in middle-skill non-STEMM fields as adults; the same is not true of the high-skill workforce. CONCLUSIONS: One-size-fits-all policies for broadening participation in the STEMM workforce across skill-level are unlikely to be successful. Further, programs that are designed to generate wonder and fascination with STEMM content may be successful in attracting more girls. However, to promote greater participation of individuals from traditionally underrepresented ethnic minority groups in STEMM, programs that support choices toward higher educational attainment, specifically four-year college degree attainment, are more likely to be successful.
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Inferior vena cava (IVC) filters are increasingly used in patients with advanced-stage cancer for prophylaxis of pulmonary embolus. We evaluated the survival benefit of placing IVC filters in patients with late-stage malignancy and assessed their effectiveness in preventing pulmonary embolism. Between 1998 and 2003, 5,970 patients were treated with a primary diagnosis of malignancy at a tertiary care facility. Retrospective analysis identified 55 consecutive patients with stage III or IV malignant disease and venous thromboembolism (VTE) who received IVC filters. Retrospective review of electronic hospital charts identified subsequent pulmonary emboli, procedure-related complications, and survival. In a case control study, 16 patients with VTE but without IVC filter were matched for age, sex, type of malignancy, and stage of disease. IVC filter placement effectively prevented computed tomography (CT) scan or ventilation/perfusion ratio (V/Q) scan-proven pulmonary embolus in 52/55 (94.5%) patients. Complications developed in 4/55 or 7.3% of patients; 13/55 (23.6%) patients with late-stage cancer survived less than 30 days following placement of the filter. Another 23.6% of this group survived longer than 1 year. Ambulatory status differed significantly (p = 0.01) between these 2 subgroups. In the case control study, IVC filter placement conferred no survival benefit compared to the control group. One recurrent pulmonary embolism was observed in both the filter group and the control group. No deaths due to thromboembolic complications were observed in either group. In late-stage cancer, patient survival is limited primarily by the malignant process. While IVC filter placement is effective in preventing pulmonary emboli, there may be limited survival benefit in this particular patient population. However, there exists a subset of this population whose functional status predicts longer survival times after filter placement.